The concept of a Smash is to extract the essential oils from spices and herbs, just as in punches and juleps, and the name it selves indicates that the particular botanicals can be smashed to get the flavors out faster than one can do in an infusion. Here's a nice palatable version.
• 6 cl. Old English Gin
• Juice from a lime
• One tablespoon sugar
• Large sprig of fresh mint
Instructions: Muddle mint and sugar with lime juice and add gin. Stir with ice and double strain into a fancy cocktail glass with crushed ice. Garnish with mint and fruits of the season. Add a straw if required.